I personally don't believe it either.. but I was first told this when I
was certified for mil-2000a soldering, and all of my research on the
topic has confirmed it. It's the residue, which consists of flux and
various other substances, some of which were formed during soldering,
that are considered corrosive. Most QA programs specify that all flux
residue has to be removed. However, there are different kinds of flux.
Plain old rosin is supposed to be totally benign. RA and RMA are more
chemically aggressive, and are not recommended for no-clean
applications. No-clean fluxes have the benefit of omitting the cleanup
step, but they are bad for soldering iron tips (go figure).. and my
iron was pretty expensive so I use RMA and scrub it off when I'm done.

This is all going to change really soon because of the industry push to
RoHS anyway.

And was this really a troll post? How can you tell? Somehow I just
don't feel properly burned...